Vehicular heat generators and viscous fluids for the same

Abstract

As a viscous fluid (F) contained in a vehicular heat generator provided with a rotor (33), a non-Newtonian fluid having an apparent viscosity that decreases as the shear rate of the rotor (33) increases (e.g., a kind of silicone oil) is employed. The nominal viscosity of the viscous fluid (F) is in the range of 10,000 cSt to 200,000 cSt. If such viscous fluid is employed, the viscous fluid (F) maintains its shear heat generating function over an extended period even under circumstances where the fluid (F) is subjected to over-shearing by over-rotation of the rotor (33). In addition, low-temperature starting of the rotor is facilitated.

We claim: 
     
       1. A viscous fluid for use in a vehicular heat generator, wherein the heat generator has a rotor that generates heat by mechanically shearing the fluid, and wherein the viscous fluid is a non-Newtonian fluid having apparent viscosity characteristics with respect to shear rate such that its apparent viscosity tends to decrease as the shear rate increases. 
     
     
       2. The viscous fluid for use in a vehicular heat generator according to claim 1, wherein the viscous fluid has a nominal viscosity within the range of 10,000 centistokes to 200,000 centistokes. 
     
     
       3. The viscous fluid for use in a vehicular heat generator according to claim 1, wherein a major component of the viscous fluid is silicone oil. 
     
     
       4. The viscous fluid for use in a vehicular heat generator according to claim 3, wherein the silicone oil in the viscous fluid contains dimethyl-polysiloxane. 
     
     
       5. A vehicular heat generator comprising: a housing;   a heating chamber within the housing;   a viscous fluid within the heating chamber having apparent viscosity characteristics with respect to shear rate such that its apparent viscosity tends to decrease as the shear rate increases and having a nominal viscosity in the range of 10,000 centistokes to 200,000 centistokes;   a radiating chamber through which a circulating fluid flows;   a rotary shaft rotatably supported in the housing; and   a rotor located in the heating chamber, wherein the rotor is rotated by the rotary shaft, and wherein heat is generated by shearing of the viscous fluid by rotation of the rotor, and wherein heat is transferred from the heating chamber to the circulating fluid.   
     
     
       6. The vehicular heat generator according to claim 5, wherein the viscous fluid is a silicone oil having non-Newtonian viscosity such that the apparent viscosity of the viscous fluid tends to decrease as the shear rate increases. 
     
     
       7. The vehicular heat generator according to claim 5, wherein the viscous fluid has a nominal viscosity in the range of 30,000 centistokes to 100,000 centistokes. 
     
     
       8. The vehicular heat generator according to claim 5, wherein the rotor is provided with means for increasing shearing efficiency, and the nominal viscosity of the viscous fluid is in the range of 15,000 centistokes to 100,000 centistokes. 
     
     
       9. The vehicular heat generator according to claim 5, further comprising a drive train located between an external drive source and the rotary shaft of the rotor, wherein the drive train includes a clutch. 
     
     
       10. A vehicular heat generator comprising: a housing;   a viscous fluid contained in the housing, wherein the viscous fluid has apparent viscosity characteristics with respect to shear rate such that its apparent viscosity tends to decrease as the shear rate increases, and wherein the viscous fluid further has a nominal viscosity in the range of 10,000 centistokes to 100,000 centistokes;   a heating chamber located within the housing, wherein a portion of the viscous fluid is stored in the heating chamber;   a reservoir located within the housing, wherein the reservoir communicates with the heating chamber, and wherein a portion of the viscous fluid is stored in the reservoir;   a radiating chamber located within the housing through which a circulating fluid flows;   a rotary shaft rotatably supported in the housing; and   a rotor located in the heating chamber, wherein the rotor is rotated by the rotary shaft, and wherein heat is generated by shearing of the viscous fluid by rotation of the rotor, and wherein heat is transferred from the heating chamber to the circulating fluid.   
     
     
       11. The vehicular heat generator according to claim 10, wherein the viscous fluid is a silicone oil having non-Newtonian viscosity such that its apparent viscosity tends to decrease as the shear rate increases. 
     
     
       12. The vehicular heat generator according to claim 10, wherein the viscous fluid has a nominal viscosity in the range of 30,000 centistokes to 100,000 centistokes. 
     
     
       13. The vehicular heat generator according to claim 10, wherein the rotor includes means for increasing shearing efficiency, and the nominal viscosity of the viscous fluid is in the range of 15,000 centistokes to 100,000 centistokes. 
     
     
       14. The vehicular heat generator according to claim 10, wherein the reservoir and the heating chamber communicate with each other via a recovery passage and a supply passage, wherein the recovery passage opens to the reservoir at a location that is above the level of the viscousfluid contained in the reservoir, and wherein the supply passage opens to the reservoir at a location that is below the level of the viscous fluid in the reservoir. 
     
     
       15. The vehicular heat generator according to claim 10, further comprising a drive train located between an external drive source and the rotary shaft of the rotor, wherein the drive train includes a clutch. 
     
     
       16. The vehicular heat generator according to claim 10, further comprising a a communicating passage that permits communication between the heating chamber and the reservoir near an axially central zone of the rotor, wherein the heat generator recovers viscous fluid from the heating chamber through the communicating passage to the reservoir, at least by the Weissenberg effect, for reducing the level of heat generation by the heat generator. 
     
     
       17. The vehicular heat generator according to claim 10, further comprising a recovery passage and a supply passage, which permit communication between the reservoir and the heating chamber, wherein the heat generator recovers viscous fluid from the heating chamber through the recovery passage to the reservoir, at least by the Weissenberg effect, for reducing the level of heat generation by the heat generator. 
     
     
       18. A method for generating heat in a vehicle which comprises providing a rotor which is capable of being driven at a plurality of rotational speeds and driving the rotor to produce mechanical shearing of a viscous fluid in contact with the rotor to generate heat, the viscous fluid being a non-Newtonian fluid having apparent viscosity characteristics with respect to shear rates in the fluid such that the apparent viscosity decreases as the shear rate increases. 
     
     
       19. A method according to claim 18 wherein the viscous fluid has a nominal viscosity withing the range of 10,000 centistokes to 200,000 centistokes. 
     
     
       20. A method according to claim 18 wherein a major component of the viscous fluid is silicone oil. 
     
     
       21. A method according to claim 20 wherein the silicone oil in the viscous fluid contains dimethylsiloxane. 
     
     
       22. A vehicular heat generator comprising: a housing;   a heating chamber within the housing;   a viscous fluid within the heating chamber, the viscous fluid being a non-Newtonian fluid that has apparent viscosity characteristics with respect to shear rate such that its apparent viscosity tends to decrease as the shear rate increases;   a radiating chamber through which a circulating fluid flows;   a rotary shaft supported in the housing; and   a rotor located in the heating chamber, wherein the rotor is rotated by the rotary shaft, and wherein heat is generated by shearing of the viscous fluid by rotation of the rotor, and wherein heat is transferred from the heating chamber to the circulating fluid.   
     
     
       23. The vehicular heat generator according to claim 22, wherein a major component of the viscous fluid is silicone oil that contains dimethyl-polysiloxane.